docs: def stream_download(self, chunk_size: Optional[int] = None, callback: Optional[Callable] = None) -> AsyncIterator[bytes]:
          """Generator for streaming request body data.
          """
          chunk_size = chunk_size or CONTENT_CHUNK_SIZE
          async def async_gen(resp):
              while True:
                  chunk = await resp.content.read(chunk_size)
                  if not chunk:
                      break
                  callback(chunk, resp)
          return async_gen(self.internal_response)